Quincy’s mayor and police chief say the Ocean Club at Marina Bay should be closed, after undercover officers made 12 arrests for the alleged possession and sale of the ecstasy drug “Molly” and cocaine there in the last three weeks.

Chief Paul Keenan said Wednesday morning that 12 “Molly” overdoses have occurred at the outdoor club since late May, including two on Aug. 31.

“For Quincy, that number is off the charts,” Keenan said of both the overdoses and arrests.

He said none of the overdoses were fatal. Only one involved a Quincy resident. The other 11 were club-goers from outside the South Shore area.

The last of the 12 arrests came Aug. 30, when police charged William Naumenko, 23, of Hull with possession of ecstasy with intent to distribute. Keenan said Naumenko was also arrested at the club Aug. 25 on the same charge.

Naumenko is the only South Shore resident to be charged. The other alleged dealers are from Dorchester, Chelmsford, Rhode Island and Connecticut.

Keenan and Quincy Mayor Thomas Koch said they'll meet with representatives of the club’s owner, Flagship Marinas, on Thursday, and ask the company to not open the Ocean Club for a scheduled Sept. 20 event.

Keenan said he and the city license board may also take further action to keep the Ocean Club from reopening in 2014.

"At this point, I'd like to see it end," Koch said of Ocean Club events.

He said a planned development project should take care of the problem. Flagship Marinas wants to build luxury apartments and more retail shops on the Ocean Club site next year. The club won't be there, "and I'm happy about that," the mayor said.

Flagship Marinas is based in Flowery Branch, Ga., a suburb of Atlanta. The company owns Marina Bay and six other luxury marina developments. A manager at the company couldn't be reached for comment Wednesday morning.

“Molly,” the street name for methylone, is suspected as the cause of three overdoses at the House of Blues in Boston last week. One of them, New Hampshire college student Brittany Flannigan, died.

Ecstasy was first a popular club drug in the 1980s. A stronger version of the drug has been available in recent months.

“Molly” is usually sold in pill form, typically for $20 each. Keenan said the overdoses in Quincy and elsewhere are because the pills now in circulation are more powerful, not because they’re from contaminated batches.

Keenan said police got the first report of ambulance calls to the Ocean Club for overdoses on May 26. The reports tapered off, then spiked again in mid-July.

He said he then met with Koch, and Lt. Patrick Glynn and other detectives began undercover surveillance and "buy-bust" purchases and arrests inside the club and in the parking lot.